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Tube amps and speaker ohms

In your opinion , do push pull amps work better with 8 ohms or 4 ohms. .I am under the impression the lower the ohms, the more power is demanded from the amp....Another question, are there low powered SET amps ,and high power SET amps?
I'm looking at a 40 watt 845 tube amp for my 8 ohm, 89 db speaker.. just cked the Thor has a 86 db W18 midwoofers(2 per cabinet) and a 88 db tweeter. Will an 845 amp rated 40 watts be able to drive the 86/88 db speaker? With authority, bass, mids, highs, in dynamic sound stage? Synergy? Or poor match?
bartokfan

Showing 2 responses by elevick

elevick
2,636 posts
 
40 watts into 89db is pushing your luck. Anything loud or dynamic may over-tax your amp and distort. Also, if you are new to tubes, 845's are not necessarily the best way to go. They are pricey and difficult to "roll" when compared to EL34's or KT-88's.

From what I know, lower impedance may run at slightly higher distortion levels. Many tube amps can handle 4 ohms or less but 8-16 ohm speakers are usually much more tube friendly.
elevick
2,636 posts
 
A 4 ohm speaker rated at 92db? Quite unusual. Lower impedance speakers are almost always much less efficient. Just a thought...
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